Recent data suggest that peer interaction is an important force in the development of normal social relationships and social skills. Over the past number of years our research has focussed on the relations between dimensions of infant behavior and preschool social behavior with an understanding of the mediating role of EEG asymmetry. We have also studied, within the general population, the developmental continuities and dis-continuities associated with behavioral inhibition and social withdrawal. We have reported that social withdrawal is a behavioral 'marker' of social anxiety in early childhood and that socially withdrawn children are less confident and competent in their interactions with peers. Over the past five years we have also performed a number of studies which suggest that the affective behavior displayed by young children in novel social situations is, in part, associated with specific patterns of frontal EEG asymmetry. And, we have documented that specific patterns of infant temperament are associated with withdrawn and inhibited behavior during the preschool period. Specifically, we have found that individual differences in the pattern of frontal EEG asymmetry are associated with the valence of affective response and the child's disposition to respond in a pro-social or withdrawn manner to peers. The research proposed in this application is designed to extend our findings on the relations between dimensions of infant behavior and preschool social behavior with an under-standing of the mediating role of EEG asymmetry. The current grant will focus on two independent samples of children who were each selected at four months of age for specific behavioral characteristics thought to be associated with behavioral inhibition. Subjects in two cohorts (N=72) and (N=120) have been seen at ages 9, 14, and 24 months of age. At each age, measures of behavioral response to novel events were recorded. At each age, brain electrical activity (EEG) was recorded from each subject. We propose to see these two cohorts when children are four years of age. At that time each child will be seen twice. Once with three others in a same sex quartet play session and once individually when EEG will be recorded. Based upon our previous work with an unselected sample of children at age four, we believe that infant temperament and frontal EEG asymmetry will predict social withdrawal and social competence at four years of age.